The Nobu Mika. Exclusive sound-sensitive "Sound Response System", increases vibration intensity as ambient sound / music is detected by built-in sensor during use. Soft, silky, seamless finish on shaft. Choice of 10 vibration levels activated via push-button. Measuring 8 Â½" x 1 1/2", the MIKA is constructed of top quality, odourless, body friendly silicone. Lightweight. splash-proof and rechargeable via USB connection or A/C power supply. The heavy duty Li-ion battery allows for up to 3 hours between charges. Materials: medical grade Silicone / ABS (base/handle). Sound Response System, 10 levels of vibration, top quality silicone, 2 motors, USB/AC power recharge, 8 Â½" x 1 1/2", splash proof.